Site-selective multicomponent synthesis of densely substituted 2-oxo dihydropyrroles catalyzed by clean, reusable, and heterogeneous TiO2 nanopowder

An efficient method for the synthesis of densely substituted 2-oxo dihydropyrroles has been demonstrated by clean, reusable, and heterogeneous catalyst titanium dioxide (TiO2) nanopowder by the four component coupling reaction of dialkyl but-2-ynedioate, two different amines, and an aldehyde. The reaction is site-selective with respect to aromatic and aliphatic amines. Environmentally benign reaction procedure, excellent yields, tolerance of varieties of functionalities in the reactants, a wide variety of products and reusability of the catalyst make the methodology highly beneficial for the synthesis of polyfunctional dihydropyrroles.